A rainy forecast has delayed the opening of the hybrid car pool/toll lanes on the 110 Harbor Freeway in Los Angeles.

The new toll lanes - which will be a first in Los Angeles County - will not open after midnight early Saturday morning as planned, according to the Los Angeles County Metropolitan Transportation Authority.

Instead, the new Express Lanes might open after 10 p.m. Saturday or early Sunday morning, said Rick Jager, spokesperson for MTA or Metro.

"We are shooting for late Saturday or early Sunday," Jager said, though he did not have a definitive time or date.

The toll lanes will allow solo drivers to use the car pool lanes if they pay a toll. All drivers must have a "FasTrak" transponder to use the lanes. So far, Metro has given out 30,000 transponders to those who've opened accounts.

Metro officials say their crews have been prevented from performing the final touches to the signs along the 11-mile stretch of the 110 car pool lanes due to the threat of rain. The hybrid car poll/toll lanes stretch from the 91 Freeway to Adams Boulevard.

Coverings have yet to be taken off the overhead signs to inform motorists that the toll lanes are active, Jager said.

"We need permission from Caltrans because of the safety concern. You don't want crews out there with slick roads," Jager said.

The National Weather Service forecasts a 40 percent chance of rain for both Friday and Saturday due to a low pressure system that will bring "scattered showers and mountain snow showers through Saturday."

"We are in a wait-and-see mode," Jager said. "This is all predicated on weather conditions, on whether our crews can get out there and uncover those signs."

The Express Lanes project is part of a one-year experimental program to study congestion pricing. The second part of the experiment is scheduled for the 10 Freeway in the San Gabriel Valley in late January or early February, according to Metro.

The lanes allow solo drivers to use the car-pool lanes while paying between $0.25 to $1.40 a mile. Car poolers are free but must have a transponder. Accounts can be obtained by going to www.metroexpresslanes.net or in person at the Gardena and El Monte Metro transit offices.